Device and method for manufacture of carbonaceous material

ABSTRACT

An apparatus and method for manufacturing a carbonaceous material are provided. The carbonaceous material manufacturing apparatus includes a reaction tube and a gas supply portion. An anode and a cathode defining an arc discharge portion is placed in the reaction tube, and a capturer is located provided as well to capture carbonaceous materials generated. At the location of the capturer, an RF heater is disposed around the reaction tube. In a carbonaceous material manufacturing method, carbonaceous materials generated in the arc discharge portion are transported from a gas supply portion into the reaction tube by the gas supplied into the reaction tube, then heated by a RF heater in the capturer where the carbonaceous materials are not exposed to the atmospheric air, to thereby promote removal of impurities and growth of single-walled carbon nanotubes.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to Japanese Patent Document No.P2001-056330 filed on Mar. 1, 2001, the disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a manufacturing method and amanufacturing apparatus of a carbonaceous material. More particularly,for the present invention relates to a manufacturing method andapparatus for single-walled carbon nanotubes or other carbonaceousmaterials by using arc discharge.

Carbon nanotubes are new materials first reported by S. Iijima inNature, Vol. 354 (1991) 56 in 1991. Especially, single-walled carbonnanotubes (SWNT) have been figured out theoretically to change inelectronic physicality from a metallic nature to a semiconductivenature, depending upon the way of winding of its helix, i.e. so-calledchirality, and it is remarked as a hopeful electronic material of thenext generation. Actually, there are various proposals of itsapplications to nanoelectronics materials, field electron emissionemitters, highly directional radiation sources, soft X-ray sources,one-dimensional conduction materials, high-heat conduction materials,hydrogen storage materials, and others. Additionally, binding functionalgroups on surfaces, metal coating or containment of foreign substanceswill further expand the range of application of carbon nanotubes.

As a method of manufacturing single-walled carbon nanotubes and othercarbonaceous materials, it has been proposed to compound a large mass ofsuch materials by a so-called arc discharge process making use of arcdischarge from a carbon rod as an electrode. This method producescarbonaceous materials by generating arc discharge in an arc dischargeportion composed of juxtaposed anode and cathode.

An example of manufacturing apparatus of carbonaceous materials relyingon an arc discharge process is shown in FIG. 1. The manufacturingapparatus 101 includes a cylindrical reaction tube 111 in which an anode113 and a cathode 114 are juxtaposed via a light distance. The anode 113is electrically connected to a positive-pole current inlet terminal 142,and the cathode 114 is electrically connected to a negative-pole currentinlet terminal 141. These two current inlet terminals 141, 142 areelectrically connected to a current supply portion 112 located outsidethe reaction tube 111 such that a voltage can be applied to the anode113 and the cathode 114. The arc discharge portion is defined by distalends where the anode 113 and the cathode 114 are opposed. The arcdischarge portion is located approximately in the center of the reactiontube 111 in its axial direction, and an electric furnace 124 for heatingthe arc discharge portion is provided outside the portion of thereaction tube 111 aligned with the art discharge portion.

The anode 113 is a carbon electrode made of carbon added with a metalfunctioning as a catalyst such as iron, cobalt, nickel, lanthanum, orthe like. The catalyst is used upon manufacturing carbonaceous materialssuch as single-walled carbon nanotubes by arc discharge. The cathode 114is a pure carbon electrode containing no catalyst.

Caps 111C, 111D covering end portions of the reaction tube 111 areprovided at opposite ends of the reaction tube 111 to be able to sealthe interior of the reaction tube 111 from the atmospheric air. The cap111C have a through hole 111 a that penetrates it in the axial directionand permits communication between the interior and the exterior of thereaction tube 111. Connected to the through hole 111 a is an inactivegas injector 143 via a hose 117. The inactive gas injector 143 cansupply inactive gas such as He or Ar into the reaction tube 111. Aflowmeter 118 is interposed in the hose 117 such that the velocity ofthe inactive gas injected into the reaction tube 111 can be changed.

The cap 111D has a through hole 111 b penetrating it in the radialdirection from its circumferential surface to permit communicationbetween the interior and the exterior of the reaction tube 111. A pump121 is connected to this through hole 111 b via a hose 119. The pump 121can discharge gas inside the reaction tube 111 to the exterior thereofby making use of a reduced pressure. A flowmeter 120 is interposed inthe hose 119 such that the velocity of inactive gas, or the like,discharged from inside the reaction tube 111.

The cap 111D has another through hole 111 c that penetrates it in theaxial direction, and receives a double tube 122 penetrating andextending beyond it. Therefore, part of the double tube 122 resides inthe reaction tube 111. On one of opposite end portions of the doubletube 122 residing in the double tube 122, a capturer 123 for capturingcarbonaceous materials produced in the arc discharge portion is mounted.The capturer 123 defined therein a space communicating with a spacedefined by the inner periphery of an outer tube and the outer peripheryof an inner tube of the double tube 122, and a space communicating witha space defined by the inner periphery of the inner tube of the doubletube 122. These two spaces are communicating with each other. In thisconfiguration, when cooled water is supplied to the space defined by theinner periphery of the inner tube from one end of the double tube 122opposite from the said end having the capturer 123, the cooled waterpasses through the space defined by the inner periphery of the innertube, then reaches the inside of the capturer 123, cools the capturer123 there, thereafter flows into the space defined by the innerperiphery of the outer tube of the double tube 122 and the outerperiphery of the inner tube thereof, and exits from the other end of thedouble tube 122.

Next explained is a method of manufacturing carbonaceous materials likesingle-walled carbon nanotubes. The anode 113 is made by crushing carbonto powder, then preparing a mixture of the powder carbon and powder of acatalyst such as iron, nickel, cobalt or lanthanum, shaping the mixtureinto the form of the anode 113, and sintering and/or machining it. Thecathode 114 is made by directly shaping carbon into the form of thecathode 114. After that, the anode 113 and the cathode 114 are set in acarbonaceous material manufacturing apparatus 101, and the interior ofthe reaction tube 111 is once evacuated to a vacuum. After that, underthe condition where an inactive gas injector 143 supplies inactive gasinto the reaction tube and the pump 121 discharges the inactive gas fromthe reaction tube 111, that is, under the condition where a gas flow ismade in the arc discharge portion, arc discharge is executed to producea carbonaceous material such as single-walled carbon nanotubes from thecarbon composing the anode 113 by catalysis of the catalyst. Morespecifically, in the arc discharge portion, metal and carbonsimultaneously vaporize from the anode 113, and the vaporizing carbonappears as soot. The soot obtained contains graphite, amorphous carbon,catalytic metal, oxides of the catalytic metal, and others in additionto single-walled nanotubes. The soot containing carbonaceous materialssuch as single-walled carbon nanotubes produced in the arc reactionportion is transported to the capturer 123 located downstream by theflow of the supplied inactive gas.

In order to increase the recovery percentage of single-walled carbonnanotubes and other carbonaceous materials produced by theabove-explained arc discharge method, various techniques have beendisclosed heretofore.

According to Japanese Patent Laid-Open Publications Nos. hei 6-157016and hei 6-280116, it is appreciated that the recovery percentage ofsingle-walled carbon nanotubes by the arc discharge method largelydepends upon the partial pressure of gas in the reaction tube where thesingle-walled carbon nanotubes are produced. Japanese Patent Laid-OpenPublication No. hei 6-280116 discloses that the recovery percentage ofsingle-walled nanotubes can be increased by maintaining the pressure ofthe inactive gas in the reaction tube in a range not lower than 200 Torr(about 26.7 kPa). Japanese Patent Laid-Open Publication No. hei 6-157016discloses that the recovery percentage of single-walled carbon nanotubescan be optimized when the partial pressure of inactive gas in thereaction tube is in the range of 500 to 2500 Torr (approximately 66.7 to333.3 kPa). Furthermore, Japanese Patent Laid-Open Publication No. hei6-157016 discloses that it is possible to increase the recoverypercentage of single-walled carbon nanotubes by adjusting thetemperature of the arc discharge portion in the range of 1000° C. to4000° C.

When single-walled carbon nanotubes are produced by the arc dischargemethod, carbonaceous materials adhere on the wall surface of thereaction tube 111 as a sootlike product or a web-like product.Single-walled carbon nanotubes are contained much more in the web-likeproduct. Sootlike products are considered to mainly comprise amorphouscarbon. Taking it into consideration, in order to obtain products richin single-walled carbon nanotubes and thereby increase the recoverypercentage, efficient recovery of web-like products is important.

Japanese Patent Laid-Open Publication No. hei 8-12310 discloses a methodof efficiently recovering web-like products containing soot generated byarc discharge. This method obtains single-walled carbon nanotubes ofhigh purity to an extent by recovering soot-contained web-like productsfrom inner wall surfaces of a reaction tube and thereafter purifying theproducts by an acidic solution or thermal oxidation.

T. Sugai et al. in Jpn. J. Appl. Phys. Vol. 38 (1999) L477 and T. Sugaiet al., in J. Chem. Phys. Vol. 112, (2000) 6000 report a method ofobtaining a high recovery percentage of single-walled carbon nanotubesby arc discharge in an electric furnace. It is reported there thatsingle-walled carbon nanotubes were evaluated by electronic microscopyor Raman spectroscopy and that more efficient recovery of single-walledcarbon nanotubes than that by arc discharge in a reaction tube wasconfirmed.

In contrast, the methods of manufacturing carbonaceous materialsdisclosed by Japanese Patent Laid-Open Publications Nos. hei 6-157016and hei 6-280116 do not include a process of purifying soot or othercarbonaceous materials obtained, and samples obtained still contain asignificant quantity of metal catalyst and amorphous carbon. Therefore,in order to increase the purity of single-walled carbon nanotubes,purification of obtained carbonaceous materials will be indispensable.Japanese Patent Laid-Open Publication No. hei 8-12310 certainly includespurification of obtained carbonaceous materials, but after removing themfrom the reaction tube and exposing them to the atmospheric air. Sincemetal catalyst is in form of fine particles, as soon as it is exposed tothe atmospheric air, its surface is oxidized. Metal catalyst, onceoxidized, is difficult to remove. Therefore, it has been difficult toobtain high-purity single-walled carbon nanotubes substantially freefrom catalyst.

SUMMARY OF THE INVENTION

The present invention provides improved methods and apparatuses formanufacturing carbonaceous materials, with which high-puritycarbon-based materials, such as single-walled carbon nanotubes can beobtained efficiently.

In an embodiment, the present invention provides a carbonaceous materialmanufacturing method in which an anode made of a carbon-based materialand a cathode made of a carbon-based material and opposed to the anodeare placed to define an arc discharge portion between the anode and thecathode in a reaction tube defining a carbonaceous material generatingchamber, the arc discharge portion producing arc to generatecarbonaceous materials when a voltage is applied across the anode andthe cathode while the arc discharge portion is exposed to an atmosphericgas, and the atmospheric gas being supplied to flow in a predetermineddirection enabling the atmospheric gas to pass through the dischargeportion in the reaction tube. The method includes recovering thegenerated carbonaceous materials in a carbonaceous material capturerlocated downstream of the arc discharge portion with respect to theflowing direction of the atmospheric gas while heating the carbonaceousmaterial capturer.

The atmospheric gas, in an embodiment, is preferably a catalytic gas.

The anode, in an embodiment, is preferably made of a carbon-family orcarbon-based material not containing a catalyst.

Alternatively, the atmospheric gas, in an embodiment, is preferably amixture gas of an organic gas and a catalytic gas.

Alternatively, the anode is, in an embodiment, preferably made of acarbon-family gas not containing a catalyst.

Alternatively, the atmospheric gas, in an embodiment, is preferably anorganic gas.

The heating of the carbonaceous material capturer is preferably carriedout under a reduced pressure in an embodiment.

The art discharge and the heating of the carbonaceous material capturerare preferably carried out simultaneously.

During the arc discharge, the atmospheric gas preferably makes a helicalflow traveling around the arc discharge portion along the lineconnecting the anode and the cathode.

Preferably, different kinds or types of atmospheric gases areindependently supplied into the reaction tube and mixed therein to makea helical flow of the mixed gas.

The invention further provides a carbonaceous material manufacturingapparatus. The apparatus includes:

a reaction tube defining a carbonaceous material generating chamber;

an anode made of a carbonaceous material and placed in the reactiontube;

a cathode made of a carbonaceous material and opposed to the anode todefine an arc discharge portion between the anode and the cathode in thereaction tube; and

a current supply portion connected to the anode and the cathode toinduce arc discharge between the anode and the cathode,

wherein an atmospheric gas supply portion is connected in communicationwith the reaction tube to supply the atmospheric gas to flow in apredetermined direction toward the arc discharge portion,

wherein a carbonaceous material capturer is located downstream of thearc discharge portion in the reaction tube with respect to the flowingdirection of the atmospheric gas, and

wherein the apparatus includes a heater located inside or outside thecarbonaceous material capturer to heat the carbonaceous materialcapturer.

The reaction tube, in an embodiment, preferably has an inner diametersmall enough to limit the flow of the atmospheric gas to one directionand prevent its convection in the reaction tube.

The atmospheric gas, in an embodiment, is preferably a mixture gas of anorganic gas and a catalytic gas.

The anode, in an embodiment, is preferably made of a carbon-familymaterial not containing catalyst.

Alternatively, the atmospheric gas, in an embodiment, is preferably acatalytic gas.

The anode, in an embodiment, is preferably made of a carbon-familymaterial not containing a catalyst.

Alternatively, the atmospheric gas, in an embodiment, is preferably anorganic gas.

Preferably, the reaction tube, in an embodiment, is approximatelyelliptic in cross section; the atmospheric gas supply portion has a gassupply tube connected to the reaction tube to supply gas toward the arcdischarge portion from an upstream position thereof to ensurecarbonaceous materials generated by arc discharge in the arc dischargeportion to be transported toward the capturer; and the gas supply tubeextends in an approximately tangential direction of the reaction tube togenerate a helical flow in the reaction tube.

The gas supply tube preferably includes, in an embodiment, at least twotubes, i.e. a first tube connected in communication in an approximatelytangential direction of the reaction tube to supply first gas into thereaction tube, and a second tube connected in communication at alocation different from that of the first tube in an approximatelytangential direction of the reaction tube to supply second gas into thereaction tube.

Preferably, a first flowmeter for permitting the first gas to flow inthe first tube at a first velocity is connected to the first tube, and asecond flowmeter for permitting the second gas to flow in the secondtube at a second velocity different from the fist velocity is connectedto the second tube, in an embodiment.

The first gas is preferably an organic gas in an embodiment.

The second gas is preferably a catalytic gas in an embodiment.

Preferably, the gas supply tube extends with an acute angle from the arcdischarge portion toward the capturer and is connected to the reactiontube in an embodiment.

Preferably, an inner tube smaller in diameter than the reaction tube iscoaxially disposed in the reaction tube to reside at least at theposition where the gas supply tube is connected in an embodiment.

The reaction tube preferably has a thinner portion around the arcdischarge portion, which has an inner circumferential cross-sectionalarea larger than the inner circumferential cross-sectional area of theremainder portion of the reaction tube in an embodiment.

Preferably, the thinner portion extends up to slightly before thecapturer, and the reaction tube is enlarged in its diameter immediatelybefore the capturer in an embodiment.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Invention and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram showing a conventional carbonaceousmaterial manufacturing apparatus.

FIG. 2 is a schematic diagram showing a carbonaceous materialmanufacturing apparatus according to an embodiment of the invention.

FIG. 3 is a schematic diagram showing a part of a reaction tube of thecarbonaceous material manufacturing apparatus according to theembodiment of the invention, where a supply tube resides.

FIG. 4 is a schematic diagram showing a thinner portion of the reactiontube of the carbonaceous material manufacturing apparatus according tothe embodiment of the invention.

FIG. 5 is a graph showing the Raman spectrum of Invention 1.

FIG. 6 is a graph showing the Raman spectrum of Comparative Example 1.

FIG. 7 is a schematic diagram showing a part of a reaction tube in anembodiment of the present invention, where the supply tube resides.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to methods and apparatuses formanufacturing carbonaceous materials. The methods and apparatuses of thepresent invention can effectively provide high-purity carbon-basedmaterials, such as single-walled carbon nanotubes.

A carbonaceous material manufacturing method and a manufacturingapparatus therefor according to an embodiment of the invention will beexplained with reference to FIGS. 2 through 4.

The carbonaceous material manufacturing apparatus 1 mainly manufacturessingle-walled carbon nanotubes. As shown in FIG. 2, the carbonaceousmaterial manufacturing apparatus includes an approximately cylindricalreaction tube 11 and a current supply portion 12. The reaction tube 11includes two portions, namely, an approximately cylindrical leftreaction tube 11A and a right reaction tube 11B. Therefore, the reactiontube 11 can be separated to the left reaction tube 11A and the rightreaction tube 11B such that single-walled carbon nanotubes can be takenout from a capturer 23, explained later. The reaction tube is made ofquartz excellent in heat resistance and having a stable chemical nature.

Rodlike anode 13 and cathode 14 are provided inside the left reactiontube 11A. The anode 13 and the cathode 14 are made of pure carbon.Diameters of the anode 13 and the cathode 14 are 10 mm and 15 mm,respectively. The anode 13 and the cathode 14 lie on a common line, andone end 13A of the anode 13 and one end 14A of the cathode 14 areopposed via a slight gap. The other end 13A of the anode 13 iselectrically connected to the positive pole of the current supplyportion 12, and the other end 14B of the cathode 14 is electricallyconnected to the negative pole of the current supply portion 12, suchthat arc discharge can be brought about between one end 13A of the anode13 and one end 14A of the cathode 14 when a current is supplied to theanode 13 and the cathode 14. A changeover switch, not shown, can revertthe polarities of the electrodes and can bring about arc discharge byreverting positions of the anode 13 and the cathode 14. Opposed distalends of the anode 13 and the cathode 14 define the arc dischargeportion. The arc discharge portion is positioned approximately at theaxial center of the left reaction tube 11A.

The anode 13 wears off because it is used as the source material ofcarbonaceous materials when carbonaceous materials such as single-walledcarbon nanotubes are manufactured. The gap between the anode 13 and thecathode 14 is maintained always constant to prevent that arc dischargedoes not occur by enlargement of the gap between the anode 13 and thecathode 14 due to the wear of the anode 13. More specifically, the otherand of the anode 13 is supported by a linear motion introducingmechanism 16 and can be moved in the lengthwise direction of the anode13. The other end 14B of the cathode 14 is supported by a support member15 that holds the cathode 14 immovable.

Opposite ends of the reaction tube 11 are covered by caps 11C, 11D, andthe interior of the reaction tube 11 is shut off from the atmosphericair. Since the opposite ends of the reaction tube are round, the caps11C, 11D covering them are round also. A supply tube 17 for supplyinggas into the reaction tube 11 merges into the reaction tube 11 at aposition slightly nearer to the arc discharge portion from the cap 11C,and the interior of the supply tube 17 communicates with the interior ofthe reaction tube 11.

As shown in FIG. 3, the supply tube 17 is configured to extendtangentially of the peripheral surface of the left reaction tube 11A.Therefore, the gas supplied to the left reaction tube 11A rushestangentially from the reaction tube 11. As a result, the supplied gasmakes a helical flow in the reaction tube 11 as shown by arrows in FIG.3, and it is supplied to the arc discharge portion in form of thehelical flow.

The supply tube 17 includes a supply tube flowmeter 18 inserted in apart thereof as a flow control means (FIG. 2). At the other end of thesupply tube 17 opposite from one end thereof connected to the reactiontube 11, a gas supply portion, not shown, is provided. The gas supplyportion can selectively supply inactive gas or mixed gas of catalyticgas and organic gas. In an embodiment, the catalytic gas includessublimed ferrocene. In an embodiment, the inactive gas includes heliumgas. In addition to the carbon of the anode, the organic gas is anothersource material of single-walled carbon nanotubes and other carbonaceousmaterials to be produced, and here is used methane gas as a simplesubstance. The supply tube flowmeter 18 can adjust the flow rate of themixed gas flowing through the supply tube 17 and supplied to thereaction tube 11. The maximum flow rate of the gas in the reaction tube11 is 5 L/min.

Since the organic gas as the source material of carbonaceous materialsto be generated is supplied to the arc discharge portion in the leftreaction tube 11A, it reduces the percentage of the anode used as thesource material of carbonaceous materials, and can greatly slow down theconsumption of the anode. Additionally, since the catalytic gas issupplied to the arc discharge portion in the reaction tube 11, the anodeneed not be prepared by mixing catalyst and carbon. This contributes toreducing the time and cost for manufacturing anodes, and single-walledcarbon nanotubes and other carbonaceous materials can be manufacturedeasily at a lower cost.

Furthermore, since the gas is supplied to the arc discharge portionwhile maintaining the helical flow, the catalytic gas and the organicgas are uniformly supplied to the arc discharge portion. Therefore,uniform discharge is ensured, and carbonaceous materials with a stablequality can be generated.

At a part of the right reaction tube 11B slightly nearer toward the arcdischarge portion from the cap 11D, a discharge tube 19 is provided todischarge gas from the reaction tube. The interior of the discharge tube19 is in communication with the interior of the reaction tube 11. Thedischarge tube 19 includes a discharge tube flowmeter 20 inserted in apart thereof. A pump 21 is provided at the other end of the dischargetube 19 opposite from one end thereof connected to the reaction tube 11.The pump 21 can discharge gas from inside the reaction tube 11 bysucking the gas by means of a reduced pressure. The discharge tubeflowmeter 20 can adjust the sucking force of the pump 21.

The round cap 11D has a rodlike capturer support member 22 extendingfrom the center thereof in the axial direction of the reaction tube 11toward the arc discharge portion. At the other end of the capturersupport member 22 opposite from one end thereof adjacent the cap 11D, acapturer 23 for capturing single-walled carbon nanotubes and othercarbonaceous materials generated in the arc discharge portion isprovided. The capturer 23 is a terete graphite rod, and one of itslengthwise ends is connected to the capturer support member 22. Thecapturer 23 extends over the length approximately from the axial centerof the right reaction tube 11B to a predetermined position nearer to thearc discharge portion. With respect to the gas flow supplied from thesupply tube 17, the predetermined position is downstream of the arcdischarge portion. In contrast, the position of the supply tube 17 isupstream of the arc discharge portion. The carbonaceous materialsgenerated in the arc discharge portion include weblike samples,amorphous carbon, graphite and catalyst by densities increasing in thisorder. Remarking the difference in density and adjusting the gas flowrate to an appropriate value, the embodiment is configured toselectively capture only weblike samples in the capturer 23 locateddownstream. Upon taking out single-walled carbon nanotubes captured bythe capturer 23, the left reaction tube 11A and the right reaction tube11B can be separated.

For the purpose of heating carbonaceous materials captured by thecapturer 23 inside the right reaction tube 11B, a RF heater 24 isprovided to surround the outer periphery of a part of the right reactiontube 11B where the capturer 23 is located. Since the RF heater 24 canheat the captured carbonaceous materials still held in the capturer 23,the carbonaceous materials obtained can undergo purification withoutbeing exposed to the atmospheric air. Therefore, it is possible toremove impurities such as Fe contained in the catalyst without oxidizingthem. Simultaneously, it is possible to rearrange any single-walledcarbon nanotubes inferior in crystalline property to those of asatisfactory crystalline property. Thereby, the percentage ofsingle-walled carbon nanotubes in the carbonaceous materials can beincreased efficiently.

As shown in FIGS. 2 and 4, the reaction tube 11 is not uniform indiameter over its full length, but it has a thinner portion 11E with asmaller diameter in a part thereof. More specifically, a part of thereaction tube 11 from the left end to a position beyond the location ofthe supply tube 17 toward the arc discharge portion extends with auniformly larger diameter to form a thicker portion 11F, but thereaction tube 11 is reduced in diameter from this position to form thethinner portion 11E that extends beyond the arc discharge portion up toa position slightly before the location of the capturer 23 downstream inthe gas flow direction. The thinner portion 11E is uniform in diameterwithin its own entire length. The reaction tube 11 again increases itsdiameter from the location just before the capturer 23 to form a thickerportion 11G with the same diameter as that of the left end portion ofthe reaction tube 11, and extends beyond the location of the dischargetube 19 to the right end of the reaction tube 11. This thicker portion11G is uniform in diameter as well throughout its own full length.Diameter of the thinner portion 11E is 30 mm whereas diameter of thethicker portions 11F and 11G is 50 mm. As such, diameters of the thickerportions 11F, 11G and the thinner portion 11E are small enough toprevent convection of the atmospheric gas in the reaction tube.

Since the part of the reaction tube in the location of the arc dischargeportion is the thinner portion 11E with the smaller diameter, and thecross-sectional area of the thinner portion 11E is smaller than thecross-sectional area of the thicker portion 11F in the location of thesupply tube 17. Therefore, it is possible to efficiently converge theorganic gas as the source material gas to the arc discharge portion asshown by arrows in FIG. 4 to ensure stable supply of the source materialgas. As a result, the embodiment can prevent undesirable dilution of theorganic gas in the arc discharge portion, and thereby ensures stabledischarge and stable generation of carbonaceous materials.

Additionally, since the thinner portion 11E extends beyond the arcdischarge portion up to immediately before the capturer 23, it canincrease the gas flow in the reaction tube 11. Thus the reaction tube 11can minimize undesirable adhesion of the generated carbonaceousmaterials on the inner circumferential surface of the span of thereaction tube 11 between the arc discharge portion and the capturer 23,and the capturer 23 can efficiently capture the carbonaceous materials.

Moreover, since the thicker portion 11G begins at the position justbefore the capturer 23 and can slow down the velocity of the gas thatflows around the capturer 23, the embodiment can minimize carbonaceousmaterials that pass through the capturer 23 without being capturedthereby.

In an embodiment, the present invention provides a manufacturing methodof carbonaceous materials such as single-walled carbon nanotubes. Beforethe manufacture of carbonaceous materials, the anode 13 is prepared.That is, carbon lumps are cut into the forms of the anode 13 and thecathode 14.

After that, the anode 13 and the cathode 14 are set in the linear motionintroducing mechanism 16 and on the support member 15, respectively, andthe reaction tube 11 is once evacuated to 10⁻¹ Pa or even lower.Thereafter, inactive gas is supplied from the gas supply portion, notshown, via the supply tube into the reaction tube 11 until the pressuretherein reaches approximately 66.7 kPa (500 Torr). Then the supply ofthe inactive gas is stopped and arc discharge is brought about in thearc discharge portion. Concurrently, mixed gas containing catalytic gasand organic gas is supplied from the gas supply portion, not shown, andthe pump 21 is simultaneously activated to discharge the gas from thereaction tube 11 and thereby make a flow of the gas in the reaction tube11. Percentage of the catalytic gas in the mixed gas is 50 wt %. In thisprocess, a pressure around 66.7 kPa is maintained in the reaction tube11, and the duration of time of the arc discharge is 30 minutes. In thisperiod, since the gas is supplied from the supply tube 17 in thetangential direction along the inner circumferential surface of the leftreaction tube 11A, it makes a helical flow especially in the location ofthe arc discharge portion in the reaction tube 11. Additionally, sincethe part of the reaction tube in the location of the arc dischargeportion is the thinner portion 11E with the smaller diameter, the mixedgas of the organic gas as the source material gas and the catalytic gasis efficiently converged to the arc discharge portion. In this state,carbonaceous materials including single-walled carbon nanotubes andothers are generated in the arc discharge portion, and transported tothe capturer 23 by the flow of the mixed gas of the organic gas and thecatalytic gas.

After the arc discharge is completed, the reaction tube 11 is evacuatedto 10⁻¹ Pa or even lower, and in this sate, the RF heater 24carbonaceous materials captured by the capturer 23 are heated by. Theheating is conducted at the temperature of 1100° C. for 30 minutes.Through the foregoing steps, high-purity single-walled carbon nanotubesare manufactured with a high efficiency.

An experiment was carried out on manufacturing methods and apparatusesof carbonaceous materials according to an embodiment of the presentinvention by comparing Inventions 1 through 6 that are carbonaceousmaterials prepared by manufacturing methods and apparatuses ofcarbonaceous materials according to an embodiment of the presentinvention with comparative examples that are carbonaceous materialsmanufactured by comparative examples. A discussion of the experiments isprovided below to illustrate without limitation the present invention.

Invention 1 was prepared under substantially the same condition of themanufacturing method and the manufacturing apparatus of carbonaceousmaterials according to an embodiment of the present invention. Thediameter of the anode was 6 mm and the anode was a composite rod made ofmetal powder and carbon with a composition of Ni=4.2%, Y=1.0% andC=94.8%. Additionally, before inducing arc discharge, the chamber wasonce evacuated to 10⁻¹ Pa or lower, and He gas was thereafter introduceduntil making air pressure of 66.7 kPa in the reaction tube 1. Whilemaintaining this air pressure, He gas was made to flow in the reactiontube 11 at the flow rate of 5 L per minute. Under this condition, directcurrent of 150 A was supplied between the anode 13 and the cathode 14thereby to generate arc for two minutes. A distance between theelectrodes was kept to adjust the potential difference between theelectrodes to 45˜50 V.

After the arc discharge was completed, the interior pressure of thechamber was held in 10⁻¹ Pa or lower, the capturer 23 was heated to andkept at 1100° C. for 30 minutes with high-frequency waves from the RFheater 24.

Invention 2 was prepared under the same conditions as those used toprepare Invention 1 except that the flow rate of He gas flowing in thereaction tube 11 was controlled to 0.5 L per minutes. Invention 3 wasprepared under the same conditions as those used to prepare Invention 1except that direct current of 200 A was applied between the electrodes.Invention 4 was prepared under the same conditions as those used toprepare Invention 1 except that, even after completing the arcdischarge, the He gas pressure of 66.7 kPa was maintained in thereaction tube without evacuating the reaction tube, and under thepressure, the capturer 23 was heated to and held at 1100° C. for thirtyminutes with high-frequency waves from the RF heater 24.

Invention 5 was prepared under the same conditions as those used toprepare Invention 1 except that the anode was a composite rod made ofmetal powder and carbon to have the composition of Co=1.2%, Ni=1.2% andC=97.6%. Invention 6 was prepared under the same conditions used toprepare Invention 1 except that the anode was a composite rod made ofmetal powder and carbon to have the composition of Co=1.2%, Ni=1.2% andC=97.6% and that, even after completing the arc discharge, the He gaspressure of 66.7 kPa was maintained in the reaction tube withoutevacuating the reaction tube, and under the pressure, the capturer 23was heated to and held at 1100° C. for thirty minutes withhigh-frequency waves from the RF heater 24.

Comparative Example 1 was prepared under the same conditions as thoseused to prepare Invention 1 except that the carbonaceous materialsaccumulating on the capturer 23 were recovered without the heatingprocess. Comparative Example 2 was prepared under the same conditions asthose used to prepare Invention 1 except that the anode was a compositerod made of metal powder and carbon to have the composition of Co=1.2%,Ni=1.2% and C=97.6% and that the carbonaceous materials accumulating onthe capturer 23 were recovered without the heating process.

Since Inventions 1 through 4 are different from Inventions 5, 6 andComparative Example 2 in composition of the anode of the carbonaceousmaterial manufacturing apparatus, Inventions 1 through 4 are comparedwith Comparative Example 1 whereas Inventions 5 and 6 are compared withComparative Example 2. Carbonaceous materials obtained in Inventions 1to 6 and Comparative Examples 1, 2 were evaluated with athermogravimetric device. For this thermogravimetric analysis (TGA),Pyris 1 TGA manufactured by PerkinElmer, Inc. was used. Each sample tobe analyzed was set in an alumina pan, and while dry air was supplied atthe flow rate of 30 ml. per minute, the sample was heated to 105° C. bythe heating rate of 5° C. per minute. Then the sample was maintained atthe temperature to thereby remove moisture therefrom. Consecutively, thesample was heated to 900° C. by the heating rate of 5° C. per minute.Using the weight of the sample after being maintained at 105° C. for onehour as its reference weight, changes in weight of the sample whileheated thereafter were evaluated. Although carbon in the carbonaceousmaterials is oxidized by the heating in the air, catalytic metals andmetal oxides remain even after they are heated to 900° C. Therefore, thequantity of the residual after the heating indicates the quantity ofcatalytic metals and metal oxides contained in the carbonaceousmaterials obtained.

As a result of the experiment, quantity of the residual was 7.5 wt % inInvention 1, 6.4 wt % in Invention 2, 4.8 wt % in Invention 3, 20.1 wt %in Invention 4, and 30.2 wt % in Comparative Example 1. Further, it was1.3 wt % in Invention 5, 5.0 wt % in Invention 6, and 11.2 wt % inComparative Example 2. Both the comparison of Inventions 1 through 4with Comparative Example 1 and the comparison of Inventions 5 and 6 withComparative Example 2 show that the quantity of the residual is less inthe Invention than in Comparative Example, and this demonstrates metalsand metal oxides in the carbonaceous materials vaporize and fly in theprocess of heating the carbonaceous materials captured by the capturer23. It is also noted from comparison of Inventions 1, 2 and 3 withInvention 4 or comparison between Inventions 5 and 6 that the quantityof the residual in Invention 4 is quite large in the former comparisonand the quantity of the residual in Invention 6 is quite large in thelatter comparison. From this fact, it is appreciated that the heating ofcarbonaceous materials captured by the capturer 23 under the evacuatedcondition promotes vaporization and flying of metals and metal oxides inthe carbonaceous materials and they are removed more effectively.

Raman spectroscopy was carried out with Invention 1 and ComparativeExample 1. As a result, as shown in FIGS. 5 and 6, the peak ofsingle-walled carbon nanotubes by the breathing mode appeared near 180cm⁻¹ in both samples. Therefore, it was confirmed that single-walledcarbon nanotubes are contained in the carbonaceous materials obtained inboth Invention 1 and Comparative Example 1. However, from comparisonbetween FIGS. 5 and 6, it is appreciated that the peak of single-wallednanotubes corresponding to the breathing mode appears more intensivelyin FIG. 5, and this demonstrates that growth of single-walled carbonnanotubes progressed in Invention 1 while the carbonaceous materialsobtained were heated.

On the other hand, in both Invention 1 and Comparative Example 1, the Dband by amorphous carbon as impurity appeared near 1350 cm⁻¹. Ascompared with FIG. 6, the peak corresponding to amorphous carbon, i.e.the D band, is smaller in FIG. 5. Therefore, it is appreciated that theheating of carbonaceous materials obtained in Invention 1 changed themfrom disordered crystalline orientation to regular crystal orientation.

The invention is not limited to the manufacturing method andmanufacturing apparatus of carbonaceous materials according to theembodiment heretofore explained, but contemplates various changed andmodifications within the scope recited in the claims. For instance, theforegoing embodiment uses the mixed gas of catalytic gas and organicgas. However, the mixed gas may be a mixture of inactive gas such as He,Ar, or the like, and catalytic gas, or a mixture of catalytic gas,organic gas and inactive gas.

Additionally, the foregoing embodiment uses sublimed ferrocene as thecatalytic gas. However, in lieu of ferrocene, also usable is any othermetallocene, such as nickelocene having Ni in lieu of Fe in ferrocene,cobaltocene (bis(cyclopentadienyl)cobalt) having Co in lieu of Fe, orthe like. Alternatively, their mixture, like that of ferrocene andnickelocene, may be used as well.

The anode 13 and the cathode 14 have been explained as being made ofpure carbon. However, in case the anode is prepared by using a materialcontaining Fe, Ni, Co, and/or others, these catalysts need not beremoved intentionally, but may be used directly.

The organic gas supplied to the reaction tube has been explained asbeing single-substance methane gas. However, it may be a singlesubstance of an alkane-family gas such as methane, ethane or butane, ortheir mixture. These examples of organic gas are especially preferable,but instead, a single substance of organic gas of alkane family, alkenefamily, alkyne family, aromatic series, or the like, or their mixture,may be used.

As the inactive gas, argon gas, neon gas, or the like, may be used inlieu of helium gas.

Percentage of the catalytic gas in the mixed gas used in the foregoingembodiment is 50 wt %. However, its percentage may be any in the rangeof 4 to 50%.

The reaction tube 11 has been explained as being made of quartz.However, it may be made of SUS304, SUS316, tantalum, molybdenum, or thelike, as well. That is, any material is acceptable provided it isweldable, high in heat resistance, chemically stable, and free frominfluences of high-frequency waves. Alternatively, only a part of thereaction tube 11 around the arc discharge portion may be made of suchmaterial.

An electric furnace or an infrared furnace may be provided in lieu ofthe RF heater 24 to heat carbonaceous materials including single-walledcarbon nanotubes captured by the capturer 23.

Instead of carrying out the heating by the RF heater 24 after completingthe arc discharge, the heating may be carried out concurrently with thearc discharge. In this case, single-walled carbon nanotubes and othercarbonaceous materials can be manufacturer in a shorter time.

Although the foregoing embodiment adjusts the air pressure in thereaction tube 11 to 66.7 kPa (500 Torr) during the arc discharge, thepressure may be controlled within the range of 13.3 to 333.3 kPa (100 to2500 Torr) approximately.

The foregoing embodiment uses only one supply tube 17 for supplyinggases to the reaction tube 11. However, a plurality of supply tubes maybe provided in tangential directions as shown in FIG. 7. Here again, thesupply tubes should be located upstream of the arc discharge portionwith respect to the gas flow direction. Additionally, different kinds ofgases may be supplied independently from different supply tubes into thereaction tube such that they are mixed in the reaction tube. Ifflowmeters are individually provided in those supply tubes toindividually determine velocities of gases supplied from the respectivesupply tubes such as velocity v1 and velocity v2, respectively, thehelical flow of the mixed gas generated in the reaction tube can bepowered, and it will be possible to supply a first gas from a first tubeand a second gas from a second tube, for example. Therefore, mixture ofdifferent gases can be controlled easily, and simultaneously, theprocess of mixing the first gas and the second gas before introducingthem into the reaction tube can be omitted. Furthermore, the first gasand the second gas mix more easily and more uniformly.

The supply tube 17 used in the foregoing embodiment for supplying gasesis configured to extend in the tangential direction with respect to theperipheral surface of the reaction tube 17. In addition to this, thereaction tube 17 may extend at an acute angle relative to the directionfrom the arc discharge portion toward the capturer and is thereafterconnected to the reaction tube. In this case, the helical flow of themixed gas generated in the reaction tube can be increased in velocity ofits part toward the downstream.

For the purpose of generating a more desirable helical flow of the mixedgas, an inner tube smaller in diameter than the reaction tube may becoaxially located in the reaction tube to extend at least over thelocation of the supply tube.

The thinner portion 11E of the reaction tube 11 has been explained asspanning from the location of the arc discharge portion up to slightlybefore the capturer 2. However, the thinner portion may be limitedmerely to the location of the arc discharge portion.

Although the foregoing embodiment configures the part of the reactiontube 11 surrounding the capturer 23 to be the thicker portion 11G, thisportion may be thinned as well such that the thinner portion 11E extendover the entire length of the right reaction tube 11B.

Although the foregoing embodiment has been explained as heating thecarbonaceous materials captured by the capturer 23 under a vacuum, itmay be conducted under a reduced pressure, or under a condition otherthan the vacuum or the reduced pressure.

Near the arc discharge portion, the reaction tube 11 may have a windowfor checking the arc discharge condition.

The supply tube 17 for supplying gases has been explained as extendingin the tangential direction of the peripheral surface of the reactiontube 17. However, it may extend in any other direction.

Although the reaction tube 11 has been explained as including thethinner portion 11E, it may be configured to have no thinner portion.

The foregoing embodiment has been explained as supplying the mixed gasof catalytic gas and organic gas to the arc discharge portion. However,inactive gas alone may be supplied instead of the mixed gas. In thiscase, however, the anode must be a carbon electrode containing catalystsimilarly to the anode 113 of the conventional carbonaceous materialmanufacturing apparatus.

According to the carbonaceous material manufacturing method in anembodiment, since the atmospheric gas is supplied to flow in apredetermined direction such that it can pass through the arc dischargeportion, carbonaceous materials generated in the arc discharge portionare transported in a predetermined direction without adhering to anywall surface in the reaction tube, and can be reliably captured by thecarbonaceous material capturer located downstream of the arc dischargeportion. Further, since the carbonaceous material capturer is heated,carbonaceous materials adhering on the capturer are heated, and growthof single-walled carbon nanotubes is promoted such that single-walledcarbon nanotubes inferior in crystalline property are rearranged tosingle-walled carbon nanotubes with a favorable crystalline property.Thereby, percentage of single-walled carbon nanotubes in thecarbonaceous materials can be increased efficiently.

According to the carbonaceous material manufacturing method recited inan embodiment using catalytic gas as the atmospheric gas, the anode canbe prepared without adding catalyst to it. Therefore, upon preparing theanode, the method can significantly reduce the work for mixing crushedcarbon and powdered catalyst, then molding the mixture, and nextsintering and machining the molded piece, and the preparation of theanode is simplified.

According to the carbonaceous material manufacturing methods in anembodiment in which the anode is made of a carbon-family material notcontaining catalyst, the anode can be prepared solely from acarbonaceous material not containing catalyst as a graphite rod, forexample.

According to the carbonaceous material manufacturing method in anembodiment in which the atmospheric gas is a mixture of organic gas andcatalytic gas, consumption of carbon by arc discharge is compensated bythe organic gas. Therefore, consumption of the anode is slowed down, andthe anode can be used for arc discharge over a longer period.Additionally, the anode can be prepared without adding catalyst to it.

According to the carbonaceous material manufacturing method inembodiment using organic gas as the atmospheric gas, consumption ofcarbon by arc discharge is compensated by the organic gas. Therefore,consumption of the anode is slowed down, and the anode can be used forarc discharge over a longer period.

According to the carbonaceous material manufacturing method in anembodiment, which heats the carbonaceous material capturer under areduced pressure, the carbonaceous materials obtained can be purifiedwithout being exposed to the atmospheric air. Therefore, sublimationspeed of the catalyst in the carbonaceous materials accumulating on thecapturer can be increased, and carbonaceous materials can be recoveredmore efficiently by removing catalyst and/or other impurities withoutoxidization thereof.

According to the carbonaceous material manufacturing method in anembodiment proceeding generation and recovery of carbonaceous materialsin parallel, the manufacture of carbonaceous materials is speeded up.

According to the carbonaceous material manufacturing method in anembodiment, which supplies the atmospheric gas in a helical flow movingin the direction along a line connecting to the anode and the cathodearound the arc discharge portion during arc discharge, uniform supply ofthe gas to the arc discharge portion is ensured, and carbonaceousmaterials generated in the arc discharge portion can be transportedefficiently to the capturer.

According to the carbonaceous material manufacturing method in anembodiment, configured to supply different kinds of atmospheric gasesindependently to the reaction tube so as to mix them in the reactiontube into the mixed gas while making its helical flow, the step ofmixing different kinds of gases beforehand can be omitted.

According to the carbonaceous material manufacturing apparatus in anembodiment including the heater located inside or outside thecarbonaceous material capturer to heat it, since the carbonaceousmaterial capturer is heated, carbonaceous materials adhering to thecapturer are heated as well. Therefore, single-walled carbon nanotubesinferior in crystalline property are rearranged to single-walled carbonnanotubes with a favorable crystalline property. Thereby, percentage ofsingle-walled carbon nanotubes in the carbonaceous materials can beincreased efficiently.

According to the carbonaceous material manufacturing apparatus in anembodiment, in which the reaction tube has a small inner diameter, itcan limit the flow of the atmospheric gas to only one direction toprevent convection of the atmospheric gas in the reaction tube.

According to the carbonaceous material manufacturing apparatus in anembodiment, using the mixed gas of organic gas and catalytic gas as theatmospheric gas, consumption of carbon by arc discharge is compensatedby the organic gas. Therefore, consumption of the anode is slowed down,and the anode can be used for arc discharge over a longer period.Additionally, the anode can be prepared without adding catalyst to it.

According to the carbonaceous material manufacturing apparatuses in anembodiment in which the anode is made of a carbon-family material notcontaining catalyst, the anode can be prepared solely from acarbonaceous material not containing catalyst as a graphite rod, forexample.

According to the carbonaceous material manufacturing apparatus in anembodiment using catalytic gas as the atmospheric gas, the anode can beprepared without adding catalyst to it. Therefore, upon preparing theanode, the method can significantly reduce the work for mixing crushedcarbon and powdered catalyst, then molding the mixture, and nextsintering and machining the molded piece, and the preparation of theanode is simplified.

According to the carbonaceous material manufacturing apparatus in anembodiment using organic gas as the atmospheric gas, consumption ofcarbon by arc discharge is compensated by the organic gas. Therefore,consumption of the anode is slowed down, and the anode can be used forarc discharge over a longer period.

According to the carbonaceous material manufacturing apparatus in anembodiment in which the reaction tube has an approximately ellipticcross section and the gas supply tube extends approximately in atangential direction of the reaction tube to generate a helical flow inthe reaction tube, carbonaceous materials generated in the arc dischargeportion can be transported efficiently to the capturer.

According to the carbonaceous material manufacturing apparatus in anembodiment in which at least the first tube and the second tube areprovided as the gas supply tube means, the helical flow of the mixed gasgenerated in the reaction tube is powered. Additionally, since the firstgas is supplied through the first tube and the second gas through thesecond tube, the control for mixing these gases is easier, and theprocess of mixing the first and second gases before introducing theminto the reaction tube can be omitted.

According to the carbonaceous material manufacturing apparatus in anembodiment capable of setting the velocity of the first gas and thevelocity of the second gas introduced into the reaction tube atdifferent velocities, the first gas and the second gas can be mixed moreeasily in the helical flow generated in the reaction tube, and themixture gas becomes more uniform in quality.

According to the carbonaceous material manufacturing apparatus in anembodiment using organic gas as the first gas, mixture of the organicgas with other gases is attained more easily.

According to the carbonaceous material manufacturing apparatus in anembodiment using catalytic gas as the second gas, mixture of thecatalytic gas with other gases is attained more easily.

According to the carbonaceous material manufacturing apparatus in anembodiment in which the gas supply tub extends at an acute angle withrespect to the direction from the arc discharge portion toward thecapturer and is thereafter connected to the reaction tube, the helicalflow of the mixed gas generated in the reaction tube can be increased invelocity of its part toward the downstream.

According to the carbonaceous material manufacturing apparatus in anembodiment additionally including the inner tube smaller in diameterthan the reaction tube and coaxially located in the reaction tube toextend at least over the location of the supply tube, the helical flowcan be shaped to be substantially uniform in diameter and can bepowered.

According to the carbonaceous material manufacturing apparatus in anembodiment in which the reaction tube includes a thinner portion aroundthe arc discharge portion to define an inner peripheral surface smallerin cross section than the remainder part of the reaction tube, the gasflow introduced into the reaction tube can be converged to the arcdischarge portion to generate carbonaceous materials more efficiently.Additionally, carbonaceous materials generated are prohibited to flyeverywhere in the reaction tube and are reliably guided in thepredetermined direction to be recovered easily.

According to the carbonaceous material manufacturing apparatus in anembodiment, in which the thinner portion of the reaction tube extends upto slightly before the capturer, it is less likely to occur thatcarbonaceous materials generated in the arc discharge portion lose theirmobility before reaching the capturer and adhere to the inner peripheralsurface of the reaction tube. Additionally, since the reaction tube isenlarged in its diameter immediately before the capturer, carbonaceousmaterials generated slow down immediately before the capturer, and thecapturer can recover them efficiently.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its intended advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

What is claimed is:
 1. A carbonaceous material manufacturing method, themethod comprising the steps of: providing an apparatus including ananode composed of a carbonaceous material and a cathode composed of acarbonaceous material and opposed to the anode such that an arcdischarge portion is defined between the anode and the cathode in areaction tube defining a carbonaceous material generating chamber,wherein the arc discharge portion produces an arc to generatecarbonaceous materials when a voltage is applied across the anode andthe cathode while the arc discharge portion is exposed to an atmosphericgas, and the atmospheric gas is supplied to flow in a predetermineddirection enabling the atmospheric gas to pass through the dischargeportion in the reaction tube; and recovering the generated carbonaceousmaterials in a carbonaceous material capturer located downstream of thearc discharge portion with respect to the flowing direction of theatmospheric gas while heating the carbonaceous material capturer.
 2. Themethod according to claim 1 wherein the atmospheric gas includes acatalytic gas.
 3. The method according to claim 2 wherein the anodeincludes a carbonaceous material not containing a catalyst.
 4. Themethod according to claim 1 wherein the atmospheric gas includes amixture of an organic gas and a catalytic gas.
 5. The method accordingto claim 4 wherein the anode includes a carbonaceous material notcontaining a catalyst.
 6. The method according to claim 1 wherein theatmospheric gas includes an organic gas.
 7. The method according toclaim 1 wherein the carbonaceous material capturer is heated under areduced pressure.
 8. The method according to claim 1 wherein the stepsof producing arc and heating of the carbonaceous material capturer areperformed concurrently.
 9. The method according to claim 1 wherein,during producing arc, the atmospheric gas is supplied allowing a helicalflow that travels in a direction connecting the anode and the cathodearound the arc discharge portion.
 10. The method according to claim 9wherein plurality of atmospheric gases are supplied to the reaction tubeindependently from each other and mixed in the reaction tube to make thehelical flow of the mixed gases.
 11. A carbonaceous materialmanufacturing apparatus comprising: a reaction tube defining acarbonaceous material generating chamber; an anode composed of acarbonaceous material and placed in the reaction tube; a cathodecomposed of a carbonaceous material and opposed to the anode to definean arc discharge portion between the anode and the cathode in thereaction tube; and a current supply portion connected to the anode andthe cathode to induce arc discharge between the anode and the cathode,wherein an atmospheric gas supply portion is connected in communicationwith the reaction tube to supply the atmospheric gas to flow in apredetermined direction toward the arc discharge portion, wherein acarbonaceous material capturer is located downstream of the arcdischarge portion in the reaction tube with respect to the flowingdirection of the atmospheric gas, and wherein a heater is located insideor outside the carbonaceous material capturer to heat the carbonaceousmaterial capturer.
 12. The apparatus according to claim 11 wherein thereaction tube has an inner diameter effective in size to limit the flowof the atmospheric gas in a direction and prevent convection of theatmospheric gas in the reaction tube.
 13. The apparatus according toclaim 11 wherein the atmospheric gas includes a mixture of an organicgas and a catalytic gas.
 14. The apparatus according to claim 13 whereinthe anode includes a carbonaceous material not containing a catalyst.15. The apparatus according to claim 11 wherein the atmospheric gasincludes a catalytic gas.
 16. The apparatus according to claim 15wherein the anode includes a carbonaceous material not containing acatalyst.
 17. The apparatus according to claim 11 wherein theatmospheric gas includes organic gas.
 18. The apparatus according toclaim 11, wherein the reaction tube is approximately elliptic in crosssection, wherein the atmospheric gas supply portion includes a gassupply tube connected to the reaction tube to supply gas from upstreamof the arc discharge portion toward the arc discharge portion allowingtransportation of carbonaceous materials generated by arc discharge inthe arc discharge portion toward the carbonaceous material capturer, andwherein the gas supply tube extends in a tangential direction of thereaction tube to make a helical flow in the reaction tube.
 19. Theapparatus according to claim 18 wherein the gas supply tube includes atleast two tubes including a first tube connected in communication withthe reaction tube in a tangential direction thereof to supply a firstgas into the reaction tube and a second tube connected in communicationwith the reaction tube in a location from that of the first tube in atangential direction of the reaction tube to supply a second gas intothe reaction tube.
 20. The apparatus according to claim 19 wherein afirst flowmeter is connected to the first tube to permit the first gasto flow at a first velocity in the first tube and a second flowmeter isconnected to the second tube to permit the second gas to flow at asecond velocity in the second tube.
 21. The apparatus according to claim19 wherein the first gas includes an organic gas.
 22. The apparatusaccording to claim 19 wherein the second gas includes a catalytic gas.23. The apparatus according to claim 18 wherein the gas supply tubeextends at an acute angle with respect to the direction from the arcdischarge portion toward the capturer and is connected to the reactiontube.
 24. The apparatus according to claim 19 wherein an inner tubesmaller in diameter than the reaction tube is coaxially disposed in thereaction tube to extend over a length at least including the locationwhere the gas supply tube is connected.
 25. The apparatus according toclaim 11 wherein a cross-sectional area of the reaction tube around thearc discharge portion is defined by a thinner portion smaller incross-sectional area than a remaining part of the reaction tube.
 26. Theapparatus according to claim 25 wherein the thinner portion extends upto slightly before the capturer such that the reaction tube increases indiameter immediately before the capturer.